http://www.golfclubshaftreview.com/shaft-spining.html - golf club shaft review
All About Spines
Pin High Enterprises - Complete Golf Club Repairs, Re-Shafting, Loft & Lie Adjustments, Shaft Spine Alignment Servicing All Makes of Golf Eqipment - Ocala, Florida
Fixing the fundamentals | by Jamie McConnell (The Els Club)
Instruction - Spine Angle and Better Drives - AvidGolfer Magazine